The present invention relates to the video arts. It finds particular application in conjunction with video periscopes and will be described with particular reference thereto. However, it is to be appreciated, that the invention will find application in conjunction with other panoramic, surveillance, and other wide angle video photography.
Periscopes, such as used in submarines, tanks, and the like, have traditionally been optical devices. Difficulties have arisen when several people needed to see the images viewed by the periscope at the same time or when the periscope images were to be permanently recorded. One technique for making permanent recordings was with a photographic camera. A camera, looking through the periscope, can only photograph the current field of view of the periscope. To view an entire 360.degree. panorama, a series of photographs were taken which could later be connected into a panoramic image of the entire panorama.
Rather than using a photographic camera and the inherent delays for developing the film, similar results have been achieved with a conventional video camera. Using a conventional video camera, a series of frames of a video image were collected as the periscope was rotated. Each of these frames was analogous to a still photographic picture. At traditional video frame rates on the order of 30 frames per second, there was significant overlap among the images. Faster rotation or slower frame rates would cause blurring. Aligning and interconnecting the frame images was time-consuming and slow compared to a 30 frame per second acquisition rate. Differences from frame to frame causes discontinuities at the interfaces. Moreover, the apparent speed of rotation of the image when the camera is rotated parallel to its line sweep axis or direction varies across each image. That is, most periscopes rotate about a vertical axis to scan a horizontal horizon or parameter and most video cameras and video monitors have a horizontal sweep.
The present invention contemplates a new and improved panoramic video system which overcomes the above-referenced problems and others.